Control system



March 8, 1966 D. 'r. MULLANEY CONTROL SYSTEM Filed May 1,

INVENTOR. flarzaZcZf/Vaflazz 6y 7 BY W W United States Patent 3,238,806 CONTRGL SYSTEM Donald T. Mullaney, Warren, Mich., assignor, by mesne Ia/fisiglnments, to William R. Buechler, Birmingham,

Filed May 1, 1963, Ser. No. 277,282 8 Claims. (Cl. 74-472) This invention relates, generally, to control lever and linkage systems and it has particular relation to foot operated hydraulic control systems for automobiles arranged and adapted to control the carburetor and the automatic transmission thereof.

It is conventional in the construction of automobiles to provide an automatic transmission through which the engine supplies power to the wheels in contact with the road. In such a construction provision is made for controlling the movement of the throttle valve of the carburetor from the accelerator pedal and also for controlling the automatic transmission. This is usually done by mechanical means involving levers, links, rods, bell cranks, pull cables, etc. The geometry changes in linkage components are usually extensive with new model introductions and the desired relationships between the accelerator pedal, carburetor throttle valve and automatic transmission can only be achieved by routing other necessary car components, such as exhaust pipes, fuel lines, gear shift rods, etc., around and away from the path of the linkage control rods and associated members which operatively interconnect the accelerator pedal with the carburetor and with the automatic transmission.

Accordingly, among the objects of this invention are: To provide for controlling the throttle valve of a carburetor and the control lever of an automatic transmission in an automobile in a new and improved manner; to maintain present displacement ratios between the accelerator pedal and the throttle valve of the carburetor and the control lever of the automatic transmission throughout the entire range of movement of the accelerator pedal; to provide a feedback to the accelerator pedal from both the throttle valve and the control lever of the automatic transmission; to operate hydraulically the control lever of the automatic transmission in response to hydraulic operation of the throttle valve by the accelerator pedal in such manner that the transmission control lever and the throttle valve are operated in fixed relation throughout their entire range of movement; and to employ flexible diaphragm pistons for moving relatively incompressible hydraulic fluid for controlling the throttle valve and the control lever of the automatic transmission.

In the drawing the single figure illustrates, diagrammatically, a preferred embodiment of this invention, only such parts of the automobile being shown as are necessary for an understanding of this invention.

A carburetor, shown generally at 10, of conventional construction is employed and it is provided with a carburetor or throttle valve lever 11 which is pivoted at 12 and is connected to a throttle valve 13 which is shown in an intermediate position between full open and full closed positions. A return spring 14, connected at 15 to the lever 11 and at its other end to an engine bracket 16, serves to bias the lever 11 and the throttle valve 13 toward the closed position. The engine bracket 16 is secured by a bolt 17 to a portion of the engine frame that is indicated at 18. An idling or closed throttle stop 19 is arranged to limit the movement of the lever 11 in the closed position of the throttle valve 13 while a full speed or open throttle stop 20 functions in the same manner for the full open position.

An automatic transmission is shown, generally, at 22 "ice and it will be understood that the engine with which the carburetor It is associated is arranged in conventional manner to transmit power through the automatic transmission 22 to a load which, in the case of an automobile, is the driving mechanism which applies torque to the wheels in contact with the ground for moving the vehicle. For controlling the automatic transmission 22 a transmission lever 23 is pivoted at 24 to the automatic transmission 22 for controlling the operation thereof in known manner. A stop 25 limits the movement of the transmission lever 23 to the closed position. Ordinarily the stop 25 is located internally of the automatic transmission 22 but, for illustrative purposes, it is shown externally thereto.

The speed at which the vehicle is operated is controlled, as is conventional, by an accelerator pedal 26 which is pivoted at 27 on a car floor pan 28. The accelerator pedal 26 is arranged to be contacted by the foot of the operator in the usual manner. The accelerator pedal 26, when depressed, engages and moves an accelerator rod 29 which is slidably mounted in an opening through a cover 31 which extends through an inclined surface of the car floor pan 28. The cover 31 forms a part of an accelerator piston andhousing assembly that is indicated, generally, at 32 and a part of which defines a pedal chamber 33 which is enclosed by a pedal chamber housing 34. It will be noted that the pedal chamber 33 is completely filled with a hydraulic fluid 35 which is preferably a liquid, the viscosity of which is substantially unaffected by temperature change and which is substantially incompressible at any operating temperature. Movable with the accelerator rod 29 is a guide piston 36 which, at one end, acts to limit the outward movement of the accelerator rod 29 by engaging the underside of the cover 31. At the other end of the guide sleeve 36 and closing otf one end of the pedal chamber 33 is a flexible accelerator diaphragm piston 37. It is secured in place centrally by a cap 38 and a nut 39 which is threaded on the end of the accelerator rod 29. This construction serves to clamp securely the central portion of the diaphragm piston 37 between the juxtaposed surfaces of the guide piston 36 and cap 38 so that a liquid tight seal is provided therebetween. The periphery 40 of the diaphragm piston 37 extends between a flange 41 extending radially from the cover 31 and a flange 42 which extends radially from the housing 34. Suitable holding means join the flanges 41 and 42 and the periphery 40 of the diaphragm piston 37 to provide a fluid tight construction and mount the housing assembly 32 on the inclined surface of the car floor pan 28. It will be observed that the intermediate portion of the diaphragm piston 37 is in the form of a reverse bend which permits a relatively long stroke of the accelerator rod 29 with a minimum of friction and no fluid loss.

The other end of the pedal chamber housing 34 is provided with a laterally extending nipple 43 over which one end of a flexible inextensible tube 44 is telescoped and securely clamped in fluid tight relation. The other end of the tube 44 is telescoped over a nipple 46 which extends laterally from an intermediate piston chamber housing 47 that defines an intermediate piston chamber 48 which forms a part of an intermediate piston and housing assembly that is shown, generally, at 49. It will be noted that the intermediate piston chamber 48 is in direct communication with the pedal chamber 43 through the flexible inextensible tube 44 and that it is filled with the hydraulic fluid 35. The other end of the housing 47 is closed off by a flexible intermediate diaphragm piston 50 which has essentially the same characteristics as described above for the diaphragm piston 37. Its periphery 51 is clamped between a radially outwardly extending flange 52 on the housing 47 and a similar flange 53' on a differential area chamber housing that is indicated, generally, at 54.

The differential area chamber housing 54 defines a differential area chamber 55 that is filled with a hydraulic fluid 56 which is separate from the body of hydraulic fluid but which has the same characteristics with respect to viscosity and compressibility. The intermediate diaphragm piston divides the composite housing formed by the housings 47 and 54 into two chambers, i.e., the differential area chamber and another chamber or the intermediate piston chamber 48. The housing 54 has a relatively large diameter section 57, which is the same as the diameter of the housing 47, and a small diameter section 58 into which one end of a push rod extension 59 extends. At its other end the push rod extension 59 extends centrally through a piston 66, the diaphragm piston 50 and through a cap 60 which is held in place by a nut 61 that is threaded on the adjacent end of the push rod extension 59. The other end of the push rod extension 59 is secured suitably to one end of a push rod 62 which extends through an opening 63 in a cover 64 and its other end is pivotally connected at 65 to the carburetor or throttle valve lever 11. Returning to the push rod extension 59, it will be noted that the guide piston 66 has the central portion of the intermediate diaphragm piston 50 clamped thereto by the cap 60 when the nut 61 is tightened. At its other end the guide piston 66 carries a radially extending guide member 67 which has sliding fit with the inner surface of the large diameter section 57 of the housing 54. This arrangement permits a slight change in the attitude of the push rod extension 59 and of the push rod 62 as the result of the pivotal connection at 65 to lever 11 and is further accommodated by the flexibility of the diaphragm piston 50 and a diaphragm piston 69.

A small diameter section 58 of the housing 54 and the cover 64 constitute a part of a carburetor throttle piston and housing assembly that is indicated, generally, at 68. The assembly includes a flexible carburetor throttle diaphragm piston 69 which has the characteristics of the diaphragm piston 37 previously mentioned. The diaphragm piston 69 serves to close off the outer end of the small diameter section 58 of the housing 54 and it is clamped centrally between a cap 70 and a guide piston 71 which are suitably secured to the push rod 62. The periphery 72 of the diaphragm piston 6-9 is clamped between a radially extending flange 73 on the small diameter section 58 of the housing 54 and a similar flange 74 at the base of the cover 64. It will be understood that the flexibility of the diaphragm piston 69 facilitates a change in the attitude of the push rod 62 and thus it is unnecessary to provide a jointed connection as would be the case if a cylindrical piston and cylinder construction were employed.

The housings 47 and 54 and the cover 64 are suitably secured together at the juxtaposed flanges between which the peripheries 51 and 72 of the diaphragm pistons '50 and 69 are clamped. An engine bracket 75 is employed for mounting the assemblies 49 and 68 at a location adjacent the carburetor 10. A bolt 76 serves to secure the engine bracket 75 in fixed position on the engine frame 18. The engine bracket 75 can be adjusted toward or away from the carburetor 10 since a slot 77 is provided in the flange overlying the engine frame \18.

In order to operate the automatic transmission 22 under the control of the accelerator pedal 26, provision is made for transmitting hydraulic fluid 56 from differential area chamber 55. For this purpose a nipple 79 is provided on the housing 54 and one end of a flexible inextensible tube 80 is telescoped over it and has a sealed connection thereto. The other end of the tube 80 is telescoped over a nipple 81 which extends laterally from a transmission control piston chamber housing 82; that defines a transmission control piston chamber 83 which is filled with the hydraulic fluid 56. It will be understood that the differential area chamber 55, the tube 80 and the chamber 83 are filled with the hydraulic fluid 56 with the result that on forward movement of the diaphragm pistons 50 and 69 and discharge of the fluid 56 from the chamber 55, the amount of hydraulic fluid 56 in the chamber 83 is correspondingly increased. The relationships are not identical since the forward movement of the diaphragm piston 50 is accompanied by a similar forward movement of the diaphragm piston 69. However, because of the differences in their diameters, an excess of the hydraulic fluid 56 is forced out of the differential area chamber 55 and into the transmission control piston chamber 83 through the tube 80. This increase in the volume of the hydraulic fluid 56 in the chamber 83 is reflected in a forward movement of a flexible transmission diaphragm piston 85 which has the same characteristics as the diaphragm piston 37 previously described. The diaphragm piston 85 closes off the end of the housing 82 opposite the end where the nipple 81 is located and it is centrally clamped by a cap 86 and a nut 87 to one end of a push rod 88 which extends through an opening 89 in a cover 90. The other end of the push rod 88 is pivotally connected at 91 to the distal end of the transmission lever 23' and it is moved about its pivot 24 in accordance with the movement of the diaphragm piston 85.

A guide member 92 is slidably mounted within the cover for guiding the push rod 88. It is carried by a guide piston 93 which has a radially inwardly extending flange 94 against which the central portion of the diaphragm piston 85 is clamped by the cap 86 as tightened by the nut 87. A return spring 95 reacts between the flange 94 and the inner side of the closed end of the cover 90 for the purpose of biasing the transmission lever 23 to the closed position against the stop 25. This end of the return spring 95 is centered by an annular flange 96 which extends around the opening 89 from the closed end f the cover 90. The periphery 97 of the diaphragm piston 85 is clamped between a flange 98 that extends radially from the housing 82 and a flange 99 that extends in a similar fashion from the cover 90. Suitable means join the flanges 98 and 99 for the purpose of providing a fluid tight connection with the periphery 97 of the diaphragm piston 85. A bracket 100 serves to mount the assembly 84 in operative position with respect to the transmission lever 23. A bolt 101 is employed for securing the bracket 100 to the frame of the automatic transmission 22, as shown.

When the accelerator pedal 26 is depressed, the accelerator rod 29 is correspondingly moved together with the diaphragm piston 37 to force the hydraulic fluid 35 from the pedal chamber 33 through the tube 44 into the intermediate piston chamber 48. Because of the displacement of fluid the intermediate diaphragm piston 50 is moved and a corresponding movement takes place of the push rod extension 59 and the push rod 62 which results in a movement of the lever 11 and a corresponding movement of the throttle valve 13.

Since the diaphragm piston 50 has a larger area than does the diaphragm piston 69, a portion of the hydraulic fluid 56 in the differential area chamber 55 is forced from it and through the tube 80 to increase the volume of the hydraulic fluid 56 in the transmission control piston chamber 83. The extent of movement of the diaphragm piston 85 depends upon its effective piston area and the volume of the hydraulic fluid 56 entering the chamber 83. This, in turn, is controlled by the arithmetic difference in the effective areas of the diaphragm pistons 50 and 69 and upon the extent of movement of the push rod exten- Sl'Oll 59. The forward movement of the diaphragm piston 85 is reflected in a corresponding movement of the transmission lever 23. Using the system arranged and constructed as described, there is always a definit r l ti r ship between the movement of the transmission lever 23 with respect to the movement of the throttle valve 13 and both movements are related to the extent that the accelerator pedal 26 is depressed. On release of the accelerator pedal 26 to any extent, the return spring 14 and the return spring 95 act to bias the carburetor or throttle valve lever 11 and the transmission lever 23, respectively, toward their initial positions. This is accompanied by a return of the hydraulic fluid 56 from the chamber 83 into the differential area chamber 55 and also a return of a portion of the hydraulic fluid 35 from the intermediate piston chamber 48 to the pedal chamber 33 and a corresponding outward movement of the accelerator rod 29.

Several advantages result from the hydraulic control system of the present invention. It makes possible a control with a high degree of accuracy of the required relationships between the accelerator pedal 26, the throttle valve 13 of the carburetor and the transmission lever 23 of the automatic transmission 22. One reason for this is that it is unnecessary to take into consideration linkage rod deflections and geometry pecularities since the flexible tubes 44 and 80 can be variably placed .as circumstances dictate. For this same reason there is .a substantial con servation of space and it is unnecessary to provide for routing linkage rods, cables and the like because the tubes 44 and 80 can be routed in any convenient manner without changing the operating characteristics of the hydraulic system.

The hydraulic system of the present invention can be readily and economically assembled. It is unnecessary to provide for making critical adjustments of control rod lengths, pedal angle adjustments, bell crank lever' starting points and the like for none of these devices is employed. The hydraulic linkage relationships of this invention are established basically by the relative proportions of the effective areas of the flexible diaphragm pistons 37, 50, 69 and 85 and their respective attachments to the operating parts associated therewith. The bodies 35 and 56 of hydraulic fluid are substantially incompressible under the conditions in which they are used in accordance with this invention and, when they are displaced by movement of the diaphragm piston 37 by the accelerator pedal 26, they act immediately upon the corresponding piston control areas and produce movements of the throttle valve 13 and transmission lever 23 in a predictable fashion that can be repeated indefinitely as long as the system remains intact. The necessary adjustment of the system is predetermined by appropriately providing the effective areas of the several diaphragm pistons and the attachment points thereof to the associated devices with which they are closely related. The force that must be exerted on the accelerator pedal 26 is determined by the forces exerted by the return springs 14 and 95 and any internal force produced by members operated by automatic transmission lever 23.

Because of the employment of the flexible diaphragm pistons 50, 69 and 85, it is possible to accommodate changes in attitude of the push rod 62 and the push rod 88 resulting from their pivotal connections at 65 and 91, respectively, to the levers 11 and 23. Since the flexible diaphragm pistons 37, 50, 69 and 85 are relatively deep, a relatively long stroke for .a given piston size is permitted. This is accompanied by low piston friction and no loss of hydraulic fluid.

The push rod extension 59 insures that the desired relationship between the cont-r01 of the throttle valve lever 11 and of the transmission lever 23 will be maintained. If the operation should be such that the throttle valve lever 11 cannot move or hangs up, force exerted by the primary fluid system including the fluid 35 cannot be transmitted to the secondary fluid system including the fluid 56.

The use of the intermediate piston chamber 48 and the differential area chamber 55 allows separate and distinct control of the transmission lever 23 apart from the control of the throttle valve 13 but always in a predetermined relationship. When the volume of the hydraulic fluid 35 in the chamber 48 is increased as the result of depression of the accelerator pedal 26, the diaphragm piston 50 is moved forwardly together with the push rod extension 59 and the push rod 62 to actuate the throttle valve 13. In addition, because of the diflerence in effective areas of the diaphragm pistons 50 and 69, the hydraulic fluid 56 in the differential area chamber 55 is compressed and a portion of it is transferred through the tube to the transmission control piston chamber 83. Actually hydraulic fluid in the tube 80 is forced out of it into the chamber 83 and is replaced by hydraulic fluid from the differential area chamber 55. A similar relationship exists between the hydraulic fluid 35 and the chambers 33 and 48. As pointed out above the amount of hydraulic fluid thus displaced is dependent upon the transverse movement of the diaphragm piston 50 and the arithmetic difference between its effective area and the effective area of the diaphragm piston 69.

What is claimed as new is:

1. For use with an engine having a throttle valve and arranged to transmit power through automatic transmission means having a transmission lever, in combination:

(a) a first fluid operating means to move said valve,

(b) a second fluid operating means to move said lever,

(c) a first fluid transmission means connecting said first and second fluid operating means whereby the same unit fluid pressure is applied to both operating means,

(d) a third fluid operating means common to said first and second fluid operating means,

(e) control means including a fourth fluid operating means, and

(f) a second fluid transmission means connecting said first and fourth fluid operating means whereby the same unit fluid pressure is applied to both operating means and whereby said first and second fluid operating means are operated to position said valve and said lever respectively in predetermined fixed relation in response to operation of said control means.

2. The invention, as set forth in claim 1, wherein means mechanically interconnect the first and third operating means and the valve is moved directly in response to operation of the control means.

3. The invention, as set forth in claim 1, wherein:

(a) the third fluid operating means is located at the smaller end of a differential area chamber and the first fluid operating means is located at the larger end thereof, and

(b) the first fluid transmission means is connected to said differential area chamber.

4. For use with an engine having a throttle valve and arranged to drive a load through automatic transmission means having a transmission lever, in combination:

(a) housing means defining small and large diameter chambers in endwise relation,

(b) first piston means closing off one end of said small diameter chamber,

(0) second piston means dividing said large diameter chamber into a differential area chamber between the two piston means and another chamber,

(d) housing means defining a transmission control chamber,

(e) third piston means closing off one end of said transmission control chamber and connected to move said lever,

"(f) a fluid conduit interconnecting said diflerential area chamber and said transmission control chamber,

(g) housing means defining a manual control chamber,

(h) a fluid conduit interconnecting said other chamber and said manual control chamber, and

(i) fourth piston means closing off one end of said manual control chamber and operable to change the fluid pressure applied to said second piston means and thereby to said first and third piston means to move said valve and said lever respectively in predetermined fixed relation.

5. The invention, as set forth in claim 4, wherein:

(a) spring means individual to the first and third piston means bias the same, and

(b) means mechanically interconnect the first and second piston means and application of fluid pressure thereto and to said third piston means by the fourth piston means causes tensioning of said spring means.

6. The invention, as set forth in claim 4, wherein the several piston means are provided by flexible relatively inextensible diaphragms.

7. For use with an engine having a throttle valve and arranged to transmit power through automatic transmission means having a transmission lever, in combination,

(a) fluid housing means defining at one end a small diameter section and at the other end a large diameter section,

(b) a first flexible diaphragm piston closing off the outer end of said small diameter section,

(c) a second flexible diaphragm piston dividing said large diameter section into a differential area chamber between said first and second pistons and another chamber at said other end of said housing means,

(d) fluid housing means defining a transmission control chamber,

(e) a third flexible diaphragm piston closing off one end of said transmission control chamber and connected to move said transmission lever against biasing means,

(If) a fluid conduit interconnecting said differential area chamber and said transmission control chamber,

(g) a relatively incompressible fluid filling said conduit, said differential area chamber and said transmission control chamber,

(h) fluid housing means defining an accelerator pedal chamber,

(i) a fourth flexible diaphragm piston closing off one end of said accelerator pedal chamber,

(j) an accelerator pedal operatively connected to said fourth flexible diaphragm for moving it inwardly of said accelerator pedal chamber,

(k) a fluid conduit interconnecting said other chamber and said accelerator pedal chamber, and

(l) a relatively incompresible fluid filling the last named conduit, said other chamber and said accelerator pedal chamber.

8. The invention, as set forth in claim 7, wherein means rigidly interconnect the first and second flexible diaphragms.

References Cited by the Examiner UNITED STATES PATENTS 1,199,640 9/1916 Vincent. 1,861,008 5/1932 Hayes.

FOREIGN PATENTS 584,505 1/ 1947 Great Britain. 108,114 8/1943 Sweden.

DAVID J. WILLIAMOWSKY, Primal} Examiner.

DON A. WAITE, Examiner.

H. S. LAYTON, Assistant Examiner. 

1. FOR USE WITH AN ENGINE HAVING A THROTTLE VALVE AND ARRANGED TO TRANSMIT POWER THROUGH AUTOMATIC TRANSMISSION MEANS HAVING A TRANSMISSION LEVER, IN COMBINATION: (A) A FIRST FLUID OPERATING MEANS TO MOVE SAID VALVE, (B) A SECOND FLUID OPERATING MEANS TO MOVE SAID LEVER, (C) A FIRST FLUID TRANSMISSION MEANS CONNECTING SAID FIRST AND SECOND FLUID OPERATING MEANS WHEREBY THE SAME UNIT FLUID PRESSURE IS APPLIED TO BOTH OPERATING MEANS, (D) A THIRD FLUID OPERATING MEANS COMMON TO SAID FIRST AND SECOND FLUID OPERATING MEANS, (E) CONTROL MEANS INCLUDING A FOURTH FLUID OPERATING MEANS, AND (F) A SECOND FLUID TRANSMISSION MEANS CONNECTING SAID FIRST AND FOURTH FLUID OPERATING MEANS WHEREBY THE SAME UNIT FLUID PRESSURE IS APPLIED TO BOTH OPERATING 